DE 40 35 528 C2 describes a connecting arrangement between a mower knife drive and a mower knife. The drive movingly linearly reciprocates a double knife cutter unit of front mowers.
The introduction of a lifting movement takes place by means of a pivotably moved driving lever and a drive pin connected to it. The drive pin represents a connecting element. A further connecting element, comprising a joint bearing, is connected to the mower knife. The joint arrangement is necessary since the drive pin is moved, due to its connection to the driving lever, following its pivot movement on a circular section path. The mower knife is only guided linearly in a reciprocating manner. The arrangement, during operation, enables constant pivotal movement of the drive pin relative to the connecting element connected to the mower knife as well as an axial displacement of the drive pin. The first connecting element, connecting to the mower knife, has a ring-shaped portion and a circular cylindrical bore. The intermediate ring, closed in a circumferential direction, is accommodated by its circular cylindrical outer face in the bore. The intermediate ring is adapted to the bore and retained in it. The intermediate ring has a hollow sphere-like inner face. On this hollow-spherical inner face, a bearing ring, closed in circumferential direction, is accommodated with a spherical outer face in a pivotable manner. The bearing ring has a circular cylindrical through bore. The drive pin slidable rests along the axis of the through bore, in the through bore, to be able to compensate positional change. This results from the movement of the drive pin with the driving lever on a circular path relative to the moving axis of the mower knife.
Mower knife drives are known where the mower knife is driven directly linearly in a reciprocating manner by a gearbox. One example is described in DE 39 31 736 C2 or DE 10 2005 048 766 A1. A driving journal of the gearbox reciprocatingly moves and is connected to a driving element of a connecting arrangement. Thus, during the movement at an optimal alignment of the gearbox and of the mower knife relative to each other, no constant relative movements need to be compensated for during the driving of the mower knife. However, EP 1 832 154 A1 shows an adjustment possibility. It enables an adaptation of the relative position of the components relative to each other during assembly. This adjustment is retained by tightening the parts. Also, an easy loosening remains possible for exchange purposes, for example of the mower knife.
However, it has been shown that increased wear occurs due to positional or manufacturing tolerances or deformations during operation when using a mower knife drive according to DE 39 31 736 C2 or DE 10 2005 048 766 A1, even with the direct linear driving of the mower knife. The increased wear is caused by one or more malpositions or inclined positions of the movement axis of the drive journal of the mower knife drive relative to the mower knife axis.